The proposed research programs are designed to gain insight at the molecular level of control processes which regulate gene expression, virus replication and cell growth -- primarily in mammalian cell-virus systems, and with an emphasis on mechanisms of transcription and translation. Specific areas of research include: The interferon system; biochemistry of inducers mechanism of induction, viral translation and transcription as sites of action; role of ds-RNA in virus-infected and normal cells; inter species hybrids and interferon induction and action; glucose transport in normal and transformed cells; measurement of secondary structure of viral and cellular RNA; role of cell surface glycoproteins in differentiation - use of the scaleless and nanomelia mutants; control of chondrocyte phenotypic expression in vitro; protein synthesis and development in chick embryo explants; mechanisms of terminal differentiation of musele; amino acid acyl synthetases as supramolecular complexes in transport phenomena; definition of cell surface receptors active in differentiation; mechanism of translation initiation with viral and natural cell mRNA; initiation factors in translation; isolation and characterization of mRNA for actin, tropomysin and myoglobin; factors involved in mRNA recognition; control of redundancy of rRNA cistrons; mechanism(s) regulating nucleolar transcription; redundancy and amplification; regulation of host protein synthesis in virus-infected cells; initiation factors for cell and viral protein synthesis; viral ds-RNA and host cell protein synthesis; mengo virus protein formation from large precursor polypeptides; ribosomal proteins and protein elongation factors; factors affecting ribonuclease-inhibitor interaction; modulation of thymidylate synthetase in normal and tumorous tissue; TTP synthesis in normal and SV40-infected and transformed cells; mutagenic DNA polymerase; inhibition of viral RNA synthesis by poly rl:rC in vitro; intrinsic interference, induction and action.